In a conventional motor, a rotating magnetic field is generated by supplying currents to coils of a plurality of phases wound on a stator so that a rotor is rotated by the rotating magnetic field. The coil currents supplied to drive the motor are switched over by a plurality of switching elements as exemplified in the patent document (JP 2002-345211A).
In this patent document, for example, the switching elements are resin-molded as semiconductor modules. The modules are mounted on a printed circuit board and connected to various electronic parts, such as coils and capacitors, through a wiring pattern of copper films formed on the printed circuit board. Since the copper films are normally as thin as less than 100 μm, a large area is needed on the printed circuit board to supply the required currents, in case the semiconductor modules and the coils may be connected by way of the printed circuit board. Thus, it is not possible to reduce a motor device in size.
It is proposed to provide coil terminals for connecting the semiconductor modules and the coils without a printed circuit. If the coil terminals and the coils are connected between the motor and the semiconductor modules, a space must be provided for placing a welding jig, which are used to connect the coil terminals and the coils by welding. It is thus not possible to reduce a motor device in size.